Background: Moyamoya syndrome associated with protein S deficiency is rarely encountered and is usually reported in paediatric cases with cerebral ischaemia.
Case report: A 32-year-old woman had symptoms of sudden-onset severe headache, projectile vomiting, impaired consciousness, and slight neck stiffness. The computed tomography scan of her brain showed primary intraventricular haemorrhage, and the subsequent four vessel cerebral angiographies revealed stage 3 to 4 Moyamoya disease according to Suzuki and Takaku's angiographic classification. The coagulation profile showed the presence of protein S deficiency. The patient was treated with external ventricular drainage and conservative management until blood clot resolution. The patient was discharged with normal neurological examination findings after her initial impaired consciousness and orientation defect gradually recovered.
Conclusion: This case report would alert physicians to the possible coexistence of Moyamoya syndrome and protein S deficiency, even in adult cases presenting with primary intraventricular haemorrhage.
Keywords: Intraventricular haemorrhage; Moyamoya syndrome; protein S deficiency.